clk: sunxi-ng: Add helper function to find closest rate

The default behaviour of clocks in the sunxi-ng driver is to select a
clock rate that is closest to but less than the requested rate.

Add the ccu_is_better_rate() helper function that - depending on the
fact if thc CCU_FEATURE_CLOSEST_RATE flag is set - decides if a rate is
closer than another rate.

Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
Link: https://lore.kernel.org/r/20230807-pll-mipi_set_rate_parent-v6-5-f173239a4b59@oltmanns.dev
Signed-off-by: Chen-Yu Tsai <wens@csie.org>

clk: sunxi-ng: Allow the CCU core to be built as a module

Like the individual CCU drivers, it can be beneficial for memory
consumption of cross-platform configurations to only load the CCU core
on the relevant platform. For example, a generic arm64 kernel sees the
following improvement when building the CCU core and drivers as modules:

before:
text data bss dec hex filename
13882360 5251670 360800 19494830 12977ae vmlinux

after:
text data bss dec hex filename
13734787 5086442 360800 19182029 124b1cd vmlinux

So the result is a 390KB total reduction in kernel image size.

The one early clock provider (sun5i) requires the core to be built in.

Now that loading the MMC driver will trigger loading the CCU core, the
MMC timing mode functions do not need a compile-time fallback.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20211119033338.25486-5-samuel@sholland.org

clk: sunxi-ng: Export symbols used by CCU drivers

For the individual CCU drivers to be built as modules, the ops structs,
helper functions, and callback registration functions must be exported.
These symbols are intended for use only by the adjacent CCU drivers, so
export them into the SUNXI_CCU namespace.

of_sunxi_ccu_probe is not exported because it is only used by built-in
OF clock providers.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20211119033338.25486-2-samuel@sholland.org

clk: sunxi-ng: Use a separate lock for each CCU instance

Some platforms have more than one CCU driver loaded: the main CCU, the
PRCM, the display engine, and possibly others. All of these hardware
blocks have separate MMIO spaces, so there is no need to synchronize
between them.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210901050526.45673-4-samuel@sholland.org

clk: sunxi-ng: Unregister clocks/resets when unbinding

Currently, unbinding a CCU driver unmaps the device's MMIO region, while
leaving its clocks/resets and their providers registered. This can cause
a page fault later when some clock operation tries to perform MMIO. Fix
this by separating the CCU initialization from the memory allocation,
and then using a devres callback to unregister the clocks and resets.

This also fixes a memory leak of the `struct ccu_reset`, and uses the
correct owner (the specific platform driver) for the clocks and resets.

Early OF clock providers are never unregistered, and limited error
handling is possible, so they are mostly unchanged. The error reporting
is made more consistent by moving the message inside of_sunxi_ccu_probe.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210901050526.45673-2-samuel@sholland.org

clk: sunxi: Don't call clk_hw_get_name() on a hw that isn't registered

The implementation of clk_hw_get_name() relies on the clk_core
associated with the clk_hw pointer existing. If of_clk_hw_register()
fails, there isn't a clk_core created yet, so calling clk_hw_get_name()
here fails. Extract the name first so we can print it later.

Fixes: 1d80c14248d6 ("clk: sunxi-ng: Add common infrastructure")
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: sunxi-ng: switch to of_clk_hw_register() for registering clks

Commit 89a5ddcc799d ("clk: Add of_clk_hw_register() API for early clk
drivers") introduces a new API for registering clks, which allows the
user to directly specify a device node, even if there is no struct
device attached to it. The device node is used for local DT clock-names
matching.

Switch to of_clk_hw_register() so that local DT clock-names matching
works.

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

Based on 3 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [kishon] [vijay] [abraham]
[i] [kishon]@[ti] [com] this program is distributed in the hope that
it will be useful but without any warranty without even the implied
warranty of merchantability or fitness for a particular purpose see
the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [graeme] [gregory]
[gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
[kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
[hk] [hemahk]@[ti] [com] this program is distributed in the hope
that it will be useful but without any warranty without even the
implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

clk: sunxi-ng: Add clk notifier to gate then ungate PLL clocks

In common PLL designs, changes to the dividers take effect almost
immediately, while changes to the multipliers (implemented as
dividers in the feedback loop) take a few cycles to work into
the feedback loop for the PLL to stablize.

Sometimes when the PLL clock rate is changed, the decrease in the
divider is too much for the decrease in the multiplier to catch up.
The PLL clock rate will spike, and in some cases, might lock up
completely. This is especially the case if the divider changed is
the pre-divider, which affects the reference frequency.

This patch introduces a clk notifier callback that will gate and
then ungate a clk after a rate change, effectively resetting it,
so it continues to work, despite any possible lockups. Care must
be taken to reparent any consumers to other temporary clocks during
the rate change, and that this notifier callback must be the first
to be registered.

This is intended to fix occasional lockups with cpufreq on newer
Allwinner SoCs, such as the A33 and the H3. Previously it was
thought that reparenting the cpu clock away from the PLL while
it stabilized was enough, as this worked quite well on the A31.

On the A33, hangs have been observed after cpufreq was recently
introduced. With the H3, a more thorough test [1] showed that
reparenting alone isn't enough. The system still locks up unless
the dividers are limited to 1.

A hunch was if the PLL was stuck in some unknown state, perhaps
gating then ungating it would bring it back to normal. Tests
done by Icenowy Zheng using Ondrej's test firmware shows this
to be a valid solution.

[1] http://www.spinics.net/lists/arm-kernel/msg552501.html

Reported-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Icenowy Zheng <icenowy@aosc.io>
Tested-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

clk: sunxi-ng: Display index when clock registration fails

Add clock index to clock registration failure message. Clock name
is sometimes not available, when things go really wrong.

Signed-off-by: Priit Laes <plaes@plaes.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

clk: sunxi-ng: Check kzalloc() for errors and cleanup error path

This kzalloc() could fail. Let's bail out with -ENOMEM here
instead of NULL dereferencing. That silences static checkers. We
should also cleanup on the error path even though this function
returning an error probably means the system won't boot.

Cc: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

clk: sunxi-ng: Support separately grouped PLL lock status register

On the Allwinner A80 SoC, the PLL lock status indicators are grouped
together in a separate register, as opposed to being scattered in each
PLL's configuration register.

Add a flag to support this.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

clk: sunxi-ng: Fix inverted test condition in ccu_helper_wait_for_lock

The condition passed to read*_poll_timeout() is the break condition,
i.e. wait for this condition to happen and return success.

The original code assumed the opposite, resulting in a warning when
the PLL clock rate was changed but never lost it's lock as far as
the readout indicated. This was verified by checking the read out
register value.

Fixes: 1d80c14248d6 ("clk: sunxi-ng: Add common infrastructure")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

clk: sunxi-ng: Fix inverted test condition in ccu_helper_wait_for_lock

The condition passed to read*_poll_timeout() is the break condition,
i.e. wait for this condition to happen and return success.

The original code assumed the opposite, resulting in a warning when
the PLL clock rate was changed but never lost it's lock as far as
the readout indicated. This was verified by checking the read out
register value.

Fixes: 1d80c14248d6 ("clk: sunxi-ng: Add common infrastructure")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

clk: sunxi-ng: Add common infrastructure

Start our new clock infrastructure by adding the registration code, common
structure and common code.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-3-maxime.ripard@free-electrons.com